Long fiber-reinforced polyamide resin composition and molded articles therefrom

Abstract

Long fiber-reinforced normally solid polyamide resin compositions and molded articles formed thereof include a polyamide base resin, between 5 to 80% by weight of reinforcing fibers having a length of at least 3 mm, and between 0.01 to 3% by weight of a processing aid. The processing aid is a lithium salt of a fatty acid or a metal salt of a fatty acid having 22 to 32 carbon atoms. The compositions are preferably in the form of a generally cylindrical pellet having a length of 3 to 50 mm such that the reinforcing fibers are substantially as long as the pellet in which they are incorporated, and are oriented parallel to one another along the longitudinal axis of the pellet.

What is claimed is: 
     
       1. A long fiber-reinforced normally solid polyamide resin composition comprising, based on the total composition weight: (A) a polyamide base resin;   (B) between 5 to 80% by weight of reinforcing fibers having a length of at least 3 mm; and   (C) between 0.01 to 3% by weight of a processing aid which is at least one selected from (C-1) a lithium salt of a fatty acid, and (C-2) a metal salt of a fatty acid having 22 to 32 carbon atoms.   
     
     
       2. The long fiber-reinforced polyamide resin composition according to claim 1, which is in the form of a generally cylindrical pellet having a length of 3 to 50 mm and wherein the reinforcing fibers are substantially as long as the pellet and oriented parallel to one another along the longitudinal axis of the pellet. 
     
     
       3. The long fiber-reinforced polyamide resin composition according to claim 1, wherein said processing aid is at least one selected from lithium, zinc, calcium and aluminum salts of behenic, montanic, melissic, lacceric and erucic acids. 
     
     
       4. The long fiber-reinforced polyamide resin composition according to claim 1, wherein said processing aid is dispersed within said composition. 
     
     
       5. The long fiber-reinforced polyamide resin composition according to claim 1, wherein said processing aid is on an external surface of said composition. 
     
     
       6. An injection-molded article which consists essentially of the long fiber-reinforced polyamide resin composition according to any one of claims 1-5. 
     
     
       7. In a method of making a long-fiber reinforced polyamide resin composition comprising incorporating between 5 to 80% by weight of reinforcing fibers having a length of at least 3 mm within a polyamide base resin, the improvement comprising incorporating said reinforcing fibers within said polyamide base resin in the presence of between 0.01 to 3% by weight, based on the total composition weight, of a processing aid which is at least one selected from a lithium salt of a fatty acid, and a metal salt of a fatty acid having 22 to 32 carbon atoms. 
     
     
       8. The process as in claim 7, which further includes forming the composition into generally cylindrical pellets having a length of 3 to 50 mm such that the reinforcing fibers are substantially as long as the pellet in which they are incorporated and are oriented parallel to one another along the longitudinal axis of the pellet. 
     
     
       9. The process according to claim 7, wherein said processing aid is at least one selected from lithium, zinc, calcium and aluminum salts of behenic, montanic, melissic, lacceric and erucic acids. 
     
     
       10. The process according to claim 7, which comprises dispersing said processing aid within said polyamide base resin. 
     
     
       11. The process according to claim 8, which comprises applying said processing aid onto an external surface of said pellets.